If it's a Y fare and you are Gold...WHY DIDN"T YOU JUST CALL IN AND GET THE UPGRADE?
You still have the right...

FROM THE GREAT CONTINENTAL ITSELF:

Full Coach (Y)/Northwest -26/-27 Fares
> Platinum/Gold Elite members - Upgrade at the time of ticketing and upon
request any time prior to departure*
> Silver Elite members - Automatic upgrade after midnight two days prior to
departure

*Upgrades requested outside the automated three-day window must contact
their Elite Priority Line and provide your ticket number for processing.